Fig. 2.

Effects of hfq mutations on sRNA-dependent activation of rpoS and flhD. (a, c) Derivatives of SG30200 (P_BAD-rpoS-lacZ) and (e) derivatives of NRD688 (P_BAD-flhD-lacZ) carrying the indicated sRNA overexpression plasmids were grown on lactose MacConkey plates containing 50 µg/ml ampicillin and arabinose (at 0.0001% for (a) and (c) and at 0.0002% for (e)) at 37 °C for 16 h. (b, d, f) β-galactosidase activity measured in wild-type and a subset of the mutant cells shown in (a, c, e). Cells were grown in LB medium containing 100 µg/ml ampicillin, 100 µM IPTG, 0.0002% arabinose at 37 °C to early stationary phase (OD₆₀₀ ~ 1.0) and assayed. Data is an average of three assays and brackets denote the standard deviation of the mean.